History of Fire Alarms: What You Didn’t Know

May 23, 2025
9 Min Read

Key takeaways

Fire detection began with night watchmen and bell towers in ancient cities.
The 1852 telegraph-based fire alarm box revolutionized emergency alerts.
Automatic fire detectors were invented in the 20th century.
Smoke detection evolved from bulky ionization units to compact dual-sensor alarms.
Modern systems use mass notifications, voice evacuation, and smart detectors.

Before blinking red lights pierced through the smoke, and long before technology was even there to send fire alerts to the fire department in the blink of an eye, there were only human voices or bells from towers that echoed through the ancient cities about a fire engulfing a building or an entire city block.

The history of fire alarm systems is not just about wires or bells or panels, but a story of civilization itself. From the Corps of Vigiles in Ancient Rome, who patrolled the streets with buckets of water and axes, to the invention of the first telegraphic fire alarm boxes in 1852 by key figures, everything contributed to the advancement of fire alarm technology. The bringing of electricity to the equation of the fire alarm system and the accidental discovery of the first smoke detector by Walter Jaegar, all the pieces started to fall into place with time.

In this blog, we are going to take you back to the time when there was only a reactive method of fighting fires and how it evolved to watchtowers and then to smart sensors. You will get to know the key figures who contributed to every chapter of the fire alarm system because, in order to know how we protect lives and properties with this amazing technology, we need to understand the centuries of trials, errors, disasters, and efforts that led us here.

The Early Days Of Fire Detection: Bucket Brigades and Bell Towers

Humans had to fight against fire for thousands of years, and societies in the early days developed some surprising ways to detect and control flames. Like, in ancient Egypt, around 2700 BCE, they built a hand-operated dual-cylinder pump (siphon) that gave a continuous supply of water during fires. And in cities like Rome, there were watchmen and groups of citizens who formed bucket brigades (human chains passing water buckets) and literally passed leather buckets of water from hand to hand.

In 6 B.C.E., Emperor Augustus institutionalized firefighting by creating the Vigiles Urbani, which became the first fire department of Rome. These Vigiles were freedmen-drawn cohorts who patrolled the streets carrying buckets, basic pumps, brooms, and hooks. They even carried some advanced tools, such as wheeled bronze siphons to squirt water, ballistae, and onagers to hurl projectiles and create firebreaks, and axes and hooks to break down the burning structures. They also soaked blankets in vinegar in order to filter smoke as a primitive respirator. The ancient Greeks also made a significant advancement in firefighting, such as Ctesibius’s double-acting pump.

After the fall of Rome and Europe, the organized bucket brigade also vanished, and they were replaced by village bucket brigades and some guards. In England, the cities of the 1600s were really dangerous. There were tightly packed wooden structures with narrow alleys, and if there was a small spark, it would result in a fire consuming multiple city blocks. After the Great Fire of London in 1666 destroyed 13,000 houses, 87 churches, and St. Paul’s Cathedral, England began experimenting with early warning systems and attempted to create an organized public fire alert mechanism to move the communities faster during a fire.

Mechanical Fire Alarm In The 17th and 18th Centuries

The fire alarms in the 17th and 18th centuries were entirely manual and depended on the human senses. There were no sensors and no automatic alerts. There were night watchmen who patrolled the streets with lanterns to alert the sleeping citizens and local firefighting teams about fire, and mechanical fire alarms began to appear in Europe. Citizens rang church bells to alert the people of fire, and these bell alarms were in pre-arranged patterns to convey the location of the fire. In the 18th century, George Hockley invented an alarm that used a network of wires and bells to warn the citizens of a fire. This mechanical system was complex and depended entirely on wires and rods through the walls. In conclusion, medieval fire detection was about reactive fire fighting that relied completely on bucket brigades, long fire hooks to pull down the burning structures, creating firebreaks, and bell towers to alert the town people of the location of the fire.

The Telegraph And The First Fire Alarm System

A new chapter in the history of fire alarm systems began after the invention of the telegraph and Morse code by Samuel Morse, an American inventor and painter, in 1837. The idea that messages could be transmitted rapidly over long distances with electrical impulses revolutionized public fire safety and emergency responses.

In Boston on April 28, 1852, William F. Channing and Moses G. Farmer invented the first municipal fire alarm system that included three bells and box circuits, forty fire alarm boxes, and sixteen alarm bells. The primary component of these fire alarm boxes was a telegraphic key and a lever, and they were connected to a central station. Whenever there was a fire, a citizen simply needed to pull the lever and crank on a box, and that would immediately send a coded telegraph fire alarm signal to alert the people at headquarters. The entire system automatically rang the bells and also identified the box number of the fire’s location. On the next day, i.e, 29th April, the fire alarm was received over this network.

The first fire alarm boxes were red-colored units that were made of cast metal and were hung on poles or walls with instructions like “For Fire Open Then Pull Down Hook”. The invention made by Channing and Farmer is sometimes called the “Electromagnetic Fire Alarm Telegraph of 1857,” and it actually sped up the emergency response. Then, in 1855, another engineer named John Gamewell acquired the rights to this system and refined the design, which is now called the manual pull station. By 1860, Boston and other cities were installing these fire telegraph boxes everywhere. It was indeed a great leap from manual bell alarms to telegraphed alerts.

Early Electrical Alarms

Later in the 19th century, there was rapid industrialization, and electricity became the nervous system of modern life. But faulty wiring and overheated equipment increased the risk of fire, and the telegraph fire alarm system wasn’t able to keep up. It still relied on manual input, and there was a need for a faster and smarter solution.

In 1890, Francis Robbins Upton, under his mentor Thomas Edison’s guidance, patented the first electrical fire alarm system. His design involved heat-sensitive electrical circuits. The logic behind the design was that when the fire increases the temperature of the surrounding area beyond a certain threshold, the circuit would be completed and would send an electrical signal to sound an alarm and send an alert to the central station. It became the first attempt to create an automatic electric fire alarm system that would detect a fire without depending on a person to notice and react.

Later, the experiments conducted by Thomas and Upton influenced the development of thermostatic fire detectors and electrically-triggered sprinklers.

The Birth Of Early Automatic Detectors

The dawn of the 20th century saw the birth of the first automatic detectors. In 1902, in Birmingham, England, George Andrew Darby patented the first automatic fire detection system. His invention was based on electrically operated heat detectors, and the system used bimetallic strips that would bend in high temperatures, which would complete the circuit and trigger an alarm.

The researchers between 1920 and 1930 were focusing on smoke detection. Walter Jaegar, a Swiss physicist, was then working to develop a sensitive gas detection system that would detect the presence of a poison gas in the environment using ionization. His logic was that if the air is ionized by a small radioactive source, it would allow the electric current to flow. So, if the poison gas enters the chamber, it would bind to ionized air molecules and disrupt the current, triggering an alarm. But Walter’s system failed to work initially. Out of frustration, he lit a cigarette, and unlike poison gas, the smoke particles somehow disrupted the ion flow. His discovery became the blueprint for modern ionization smoke detectors.

It was a massive turning point as the detection of fire no longer depended only on heat but also on combustible particles. Later in 1939, another Swiss physicist, Dr. Ernst Meli, refined the sensitivity and reliability of the ionization chamber device to detect even smaller smoke particles. His ionization alarm was capable of detecting combustible gases in mines, and it included a small radioactive source (typically Americum-241) and a cold cathode tube to amplify the small signal generated by the detection mechanism, which was strong enough to activate an alarm.

The Rise Of Smoke Alarms

Although smoke detectors existed, they were bulky and expensive. It was not until the mid-20th century that home smoke alarms became a practical concept. In 1965, Duane Pearsall (an engineer in Colorado) and Stanley Bennett Pearson developed the first battery-powered smoke detector for homes that was affordable and called it SmokeGard-700. It was shaped like a beehive, was made of fire-resistant steel, and had a replaceable battery system. There were some early studies that showed these detectors were able to detect fire faster than heat sensors, especially for smoldering fires.

However, in a short time, there was a subsequent leap to photoelectric detectors. In 1972, Donald Steele and Robert Emark patented a light-based smoke alarm. In these devices, a beam of light would scatter when smoke enters the chamber, triggering the alarm. Photoelectric alarms were great at detecting small, smoldering fires like smoke from cigarettes, and they complemented the ionization alarms. Since then, most homes, industrial facilities, and commercial buildings use both to ensure comprehensive coverage, as photoelectric alarms are less susceptible to false alarms.

Modern Fire Alarm Systems In The 21st Century

Fire Alarm Initiation Technology

Fire alarm initiation technology has evolved greatly. The iconic red pull station that was devised by Gamewell has now become the modern manual pull station with an improved design that has break glass and slide covers to prevent false alarms. Automatic detectors now not only include smoke and heat detectors but also other initiating devices such as carbon monoxide detectors, beam detectors, linear heat cables, and flame detectors. These specialty initiating devices are required by different occupancies based on the NFPA (National Fire Protection Association) and building codes. That’s why a modern fire alarm system often includes a mix of manual stations, smoke and heat detectors, duct detectors for HVAC, pull stations, and other special devices to meet the requirements.

Mass Notification and Voice Evacuation System

Modern fire alarm systems are more than just local bells. Mass Notification Systems (MNS) are there to alert building occupants of any emergency, using voice, text, sirens, or speakers. After horrifying events like 9/11, NFPA (National Fire Protection Association) expanded the guidelines in NFPA 72 (National Fire Alarm and Signaling Code) for mass notification systems (MNS) along with traditional fire alarm systems. Voice evacuation systems have also become common in high-rise buildings. They use pre-recorded voices and microphones to alert the occupants instead of just horns and bells.

Communication technology has also evolved. There are traditional panels that communicate alarms via telephone lines and radio, but now many use fire-rated cellular communications to send alerts to emergency services. Some addressable systems also integrate with smartphone apps or building automation, sending push notifications to the security staff.

Standards and Compliance

Manufacturers now have to submit alarms, detectors, panels, and notification devices to UL/FM labs for “listing” and “approval”, to make sure that they meet safety standards. Underwriters Laboratories (UL) and FM Global are two testing organizations, and in terms of NFPA, “listed” often means an approved equipment list (often UL) while “approved” means acceptable to the authorities having jurisdiction (fire marshals in most cases). In conclusion, there are dozens of documents from UL, FM, NFPA, and other local codes that collectively dictate how modern fire alarm systems must perform.

Conclusion

The history of fire alarm started with bucket brigades in ancient Rome and bell towers in medieval towns, and evolved into telegraphic fire alarm systems in the 19th century with the help of William F. Channing and Farmer. The evolution continued as Francis Upton invented the electrical fire alarm system, George Darby developed automatic detectors, and Meli advanced the smoke sensing capability in the 20th century. Fire alarms now are no longer bell towers; they have evolved into an intelligent system that is powered by AI, integrated with mass notification systems, and holds to rigorous safety standards like those from UL and the NFPA. They not only alert but also detect fires even before they have the possibility to occur. It shows how far we have come. From cries in the night to cloud-based detection, fire alarm systems have evolved with the growing complexity of human life.